TW201814194A - Resin pipe fitting - Google Patents

Abstract

A resin pipe fitting is provided which can improve pull-out preventing performance of one end in the longitudinal direction of the joined tube. This resin pipe fitting 1 is provided with: a fitting main body 11 which has a cylindrical part 22 into which one end 5 of a tube 2 in the longitudinal direction can be inserted; an inner ring 12 which has a press-fitting part 31 which can be press-fitted on the one end of the tube in the longitudinal direction; and a union nut 13 which has a connecting part 46 that can be screwed onto the outer periphery of the fitting main body such that said connecting part 46 and the press fitting part radially clinch the one end of the tube in the longitudinal direction. Further, the inner ring and the union nut are configured using a resin material, and have the property of contracting with change in the ambient temperature. The radial contraction factor in the linking part of the union nut is set to be 0.05% or more greater than the radial contraction factor in the press fitting part of the inner ring.

Description

   Resin pipe joint   

The present invention relates to a resin pipe joint.

Conventionally, a resin pipe joint that can be used in a manufacturing apparatus in a technical field such as semiconductor manufacturing, medical and pharmaceutical manufacturing, food processing, and chemical industry is known (for example, refer to Patent Document 1). This type of resin pipe joint connects a pipe for circulating a fluid such as ultrapure water, a chemical solution, and other pipes or fluid devices, and is configured to be joined to one end portion of the pipe in the longitudinal direction.

The resin pipe joint includes a joint body, an inner ring, and a joint nut for joining the one end portion in the longitudinal direction of the pipe, and inserts the inner ring and the one end portion in the longitudinal direction of the pipe into which the pipe is pressed. The joint body is held by the joint nut so that the one end portion of the pipe in the longitudinal direction is not pulled out from the joint body.

The resin pipe joint is often subjected to a thermal cycle during use (a specific example: normal temperature (about 25 ° C) → high temperature (about 200 ° C) → normal temperature). When an unexpected extraction force is applied to the pipe joined to the resin pipe joint after a heat cycle load, the pipe may be pulled out of the joint body so as to be separated from the resin pipe joint. Therefore, it is desired to improve the pull-out resistance of the pipe of the resin pipe joint.

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-054489

The present invention has been made in view of such circumstances, and an object thereof is to provide a resin pipe joint capable of improving the pull-out resistance of one end portion in the longitudinal direction of the joined pipes.

The present invention relates to a resin pipe joint that can be joined to the pipe in a state where one end of the pipe in the longitudinal direction is inserted into the pipe, and includes a joint body having a cylindrical portion capable of inserting one end of the pipe in the longitudinal direction. An inner ring having a press-fitting portion that can be press-fitted to the lengthwise one-end portion side of the tube and can be pressed into the tube in a state of being pushed-in to the lengthwise one-end portion side of the tube One end portion in the longitudinal direction is inserted into the tube portion together; and a joint nut includes a connecting portion that can connect the press-fit portion and the tube in order to connect the one end portion side in the longitudinal direction of the tube to the joint body. In a state where one end portion in the longitudinal direction is inserted into the cylindrical portion together, the one end portion in the longitudinal direction of the tube is screwed between the radial direction and the press-fitting portion to the outer peripheral portion of the joint body; the inner ring and The joint nut is made of a resin material, and each has a property of shrinking in accordance with a change in ambient temperature. The radial direction of the connection portion of the joint nut The shrinkage ratio is set to be 0.05% or more larger than the shrinkage ratio in the radial direction of the press-fit portion of the inner ring.

With this configuration, in a state where the pipe is joined to the resin pipe joint, when the inner ring and the joint nut are heated due to heat transfer from a fluid or the like and then cooled (when a heat cycle is applied to the load), The connection portion of the engagement nut can be shrunk in the radial direction more than the press-fit portion of the inner ring.

Therefore, when the resin pipe joint is joined to the pipe, the shrinkage amount of the inner diameter of the connection portion of the joint nut is larger than the shrinkage amount of the outer diameter of the press-fitting portion of the inner ring. In the tube in which the inlet portion is supported from the inside in the radial direction, the holding force from the outside in the radial direction is strengthened by the connection portion that overlaps through the cylindrical portion of the joint body in the radial direction.

With this, when a pulling force is applied to the pipe so that the pipe is pulled out from the resin pipe joint, the joint body of the joint nut can be pressed toward the inside of the joint body by the connecting portion of the joint nut. The friction generated between the tube portion and the tube increases. Therefore, the pull-out resistance of the pipe of the resin pipe joint can be improved.

According to another aspect of the present invention, the inner ring and the joint nut are made of the same resin material.

According to another aspect of the present invention, the inner ring and the joint nut are made of different resin materials.

According to another aspect of the present invention, the joint nut has a pressing portion in a state where the press-fitting portion is inserted into the tube portion together with one end portion in the longitudinal direction of the tube, and the connecting portion is pressed against the tube along with the connecting portion. The outer peripheral portion of the portion is screwed in, and the one end portion side of the longitudinal direction of the tube can be pressed from the outside in the radial direction toward the pressing portion; the shrinkage rate in the radial direction of the pressing portion of the engaging nut is set to be smaller than The shrinkage rate in the radial direction of the press-fit portion is larger.

With this configuration, when the inner ring and the joint nut are heated due to heat transfer from a fluid or the like and then cooled, the pressing portion of the joint nut can be made similar to the connecting portion to the press-fitting portion of the inner ring. Shrink more in the radial direction.

Therefore, when the resin pipe joint is joined to the pipe, the shrinkage amount of the inner diameter of the pressing portion of the joint nut is larger than the shrinkage amount of the outer diameter of the press-fitting portion of the inner ring. The longitudinal direction one end portion side of the tube that the inlet portion is supported from the inside in the radial direction is reinforced by the pressing portion that overlaps in the radial direction from the holding force from the outside in the radial direction.

Thereby, when a pulling force is applied to the tube in order to pull out the tube from the resin tube joint, friction between the pressing portion of the joint nut outside the connector body and the tube can be caused. Force rises. Therefore, the pull-out resistance of the pipe of the resin pipe joint can be further improved.

According to the present invention, it is possible to provide a resin pipe joint capable of improving the pull-out resistance of one end portion in the longitudinal direction of the joined pipe.

1‧‧‧ resin pipe joint

2‧‧‧ tube

5‧‧‧ One end of the tube in the length direction

11‧‧‧ Connector body

12‧‧‧ inner ring

13‧‧‧Joint nut

22‧‧‧ Outer tube (tube)

31‧‧‧Press-in Department

46‧‧‧Joint Department

47‧‧‧Pressing section

101‧‧‧resin pipe joint

112‧‧‧Inner Ring

113‧‧‧Joint nut

[FIG. 1] A cross-sectional view showing a joint structure between a resin pipe joint and a longitudinal end portion of a pipe according to a first embodiment of the present invention.

[FIG. 2] A diagram showing a part of dimensions of an inner ring and a joint nut of each of Example 1 and Example 2 of the first embodiment of the present invention.

[FIG. 3] A diagram showing a part of dimensions of an inner ring and a joint nut of each of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 of the first embodiment of the present invention.

[Figure 4] Based on the description in Figure 2 or Figure 3, the inner ring and joint of each of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are shown. Graph of shrinkage of nut.

[FIG. 5] A diagram showing the pull-out resistance of the tube of each of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

[FIG. 6] A cross-sectional view showing a joint structure between a resin pipe joint and a longitudinal end portion of a pipe according to a second embodiment of the present invention.

7 is a view showing a part of dimensions of an inner ring and a joint nut of each of Example 3 and Example 4 of the second embodiment of the present invention.

8 is a view showing a part of dimensions of an inner ring and a joint nut of each of Comparative Example 5, Comparative Example 6, and Comparative Example 7 according to a second embodiment of the present invention.

[Figure 9] The shrinkage of the inner ring and the joint nut of each of Example 3, Example 4, Comparative Example 5, Comparative Example 6 and Comparative Example 7 is shown in the description of Figure 7 or Figure 8. Rate graph.

[Fig. 10] Fig. 10 is a graph showing the pull-out resistance of the tubes of each of Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

The resin pipe joint 1 according to the first embodiment of the present invention is a manufacturing device or the like that can be used for semiconductor, liquid crystal, or organic EL (Electro-Luminescence). The resin pipe joint 1 is used as shown in FIG. 1 in order to connect the pipe 2 to another pipe (not shown), or a fluid device such as a valve or a pump when the pipe joint 1 is used in the manufacturing apparatus or the like. Is configured to be capable of being joined to the tube 2.

The said resin pipe joint 1 is a state where one end part 5 of the said pipe 2 in the longitudinal direction can be inserted into the said resin pipe joint 1, and it joins the said pipe, and it has the joint main body 11, the inner ring 12, and the joint screw Cap 13. In this embodiment, the tube 2 is a cylindrical member having a substantially constant inner diameter and is made of a resin material such as a fluororesin material.

In the following description, one side in the axial direction means the tube 2 side of the resin pipe joint 1 in the first figure, and the other side in the axial direction means the resin pipe joint 1 in the first figure. The connector body 11 side.

The joint body 11 includes a cylindrical portion (an outer cylindrical portion 22 to be described later) into which the one end portion 5 in the longitudinal direction of the tube 2 can be inserted. The joint body 11 further includes a fluid flow path 16. The fluid flow path 16 is provided at the one end portion 5 of the longitudinal direction of the tube 2 when the fluid flow path 7 of the tube 2 is connected to the outer tube portion 22 (the receiving port portion 15). The inside of the aforementioned joint body 11.

The joint body 11 is made of a predetermined resin material. Preferably, the joint body 11 is made of a fluororesin material as in this embodiment. Specific examples of the fluororesin material include PFA (perfluoroalkoxyfluororesin), PTFE (polytetrafluoroethylene), and ETFE (ethylene-tetrafluoroethylene copolymer).

In this embodiment, the joint main body 11 includes a main body cylindrical portion 21, the outer cylindrical portion 22, and an inner cylindrical portion 23. The main body cylindrical portion 21 has a cylindrical portion and has a first fluid flow path 24 capable of communicating with the fluid flow path 7 of the tube 2. The first fluid flow path 24 has a substantially circular cross section, and is provided along the axial direction inside the body cylindrical portion 21 so as to form a part of the fluid flow path 16.

The outer cylindrical portion 22 is provided with a screwing portion capable of being screwed with the engaging nut 13, and is coaxial with the axial direction of the main body cylindrical portion 21 from one side end portion of the main body cylindrical portion 21 so as to form the receiving opening portion 15. To highlight settings. The outer tube portion 22 is formed in a cylindrical shape and includes the mouthpiece portion 15 inside. The screwing portion is a male screw portion 25 and is provided along an axial direction on an outer peripheral portion of the outer cylindrical portion 22.

The inner tube portion 23 is disposed inward in the radial direction of the outer tube portion 22. The inner tube portion 23 has a protruding end portion 26, and the protruding end portion 26 is located on the body tube portion 21 side from the body tube portion 21 so that the protruding end portion 26 is located on the body tube portion 21 side. One end portion in the axial direction of 21 is provided coaxially and protrudes in the same direction as the outer cylindrical portion 22 (in the axial direction of the main body cylindrical portion 21).

The inner tube portion 23 has an inner diameter substantially the same as the inner diameter of the main body tube portion 21, and has a second fluid flow path 28 formed to have a smaller diameter than the inner diameter of the outer tube portion 22. It has a cylindrical shape with an outer diameter of 550 mm and can communicate with the fluid flow path 7 of the tube 2. The second fluid flow path 28 has a substantially circular cross section, and the first fluid flow path 24 is coaxially successively provided in the first fluid flow path 24 so as to form the fluid flow path 16 together with the first fluid flow path 24. .

The joint main body 11 further includes a groove portion 29 formed so as to be surrounded by the main body cylindrical portion 21, the outer cylindrical portion 22, and the inner cylindrical portion 23 so as to open in one direction in the axial direction. The groove portion 29 is also formed as a ring extending along the entire periphery of the outer peripheral surface of the inner tube portion 23 so that the other end portion (the socket portion 36 described later) in the axial direction of the inner ring 12 can be pressed in. shape.

The inner ring 12 is provided with a press-fitting portion 31 capable of press-fitting one end portion 5 side of the tube 2 in the longitudinal direction. The press-fitting portion 31 is configured to be inserted into the outer tube portion together with the longitudinal end portion 5 of the tube 2 in a state where it is pressed into the longitudinal end portion 5 of the tube 2 from the opening portion 8. The receiving part 15 of 22 (the inside of the said connector main body 11).

In this embodiment, the inner ring 12 has an insertion portion 32 that can be inserted into the receiving portion 15 of the joint body 11 in addition to the press-fitting portion 31. The insertion portion 32 includes a fitting portion 35, the socket portion 36, and a contact portion 37. The inner ring 12 further includes a fluid flow path 38 capable of communicating the fluid flow path 7 of the tube 2 with the fluid flow path 16 of the joint body 11.

In detail, the outer peripheral shape of the press-fitting portion 31 is the same shape as the inner peripheral shape of the tube 1 in the longitudinal direction end portion 5 (the portion whose diameter is expanded by being pressed into the press-fitting portion 31) (cylinder Shape), and is disposed on one side of the inner ring 12 in the axial direction. The press-fitting portion 31 has an inner diameter substantially the same as the inner diameter of the tube 2 (the inner diameter in an unexpanded state, and the same applies hereinafter), and is included in the axial direction of the fluid flow path 38. The internal way of one side part is set. Here, the fluid flow path 38 has a substantially circular cross section.

The press-fitting portion 31 is configured to further have an outer diameter larger than the inner diameter of the tube 2 and to expand the diameter of one end portion 5 of the tube 2 in the longitudinal direction to one end in the length direction of the tube 2. The inner peripheral surface on the part 5 side is crimped over the entire circumference, and while being pressed into the longitudinal direction end portion 5 side of the tube 2 from the opening portion 8, the longitudinal end portion of the tube 2 can be specified in a specific manner. The press-in position is maintained.

In addition, the press-fitting portion 31 is configured to be capable of not changing the press-fitting position with respect to the one end portion in the longitudinal direction of the tube 2 in a state where it is press-fitted to the one end portion 5 side in the longitudinal direction of the tube 2. Together with one end 5 in the longitudinal direction of the tube 2, it is inserted into the receiving portion 15 (the inside of the joint body 11) of the outer tube portion 22 from the other side in the axial direction of the press-fitting portion 31.

When the press-fitting portion 31 is inserted into the receiving portion 15 of the outer cylindrical portion 22, the longitudinal end portion 5 of the tube 2 is sandwiched between the tube 2 and the outer cylindrical portion 22. That is, the press-fitting portion 31 is crimped to the one end portion 5 in the longitudinal direction of the tube 2 from the inside in the radial direction and covers the entire length in the axial direction, and the outer tube portion 22 covers the entire circumference and the entire length in the axial direction from the outside in the radial direction. Ground is connected to one end portion 5 in the longitudinal direction of the tube 2.

The press-fitting portion 31 further includes a bulging portion 39. The bulging portion 39 can improve the sealing performance between the two when the press-in portion 31 is pressed toward the one-end portion 5 side of the length direction of the tube 2 and is used to stop the tube 2. The detached annular convex portion is formed so as to bulge outward in the radial direction of the inner ring 12 on one side in the axial direction of the press-fitting portion 31.

The bulged portion 39 has a first outer peripheral surface and a second outer peripheral surface including a tapered shape that is disposed so as to face one of the axial direction and the other through the top (the outermost end in the radial direction). Convex shape. The second outer peripheral surface of the bulged portion 39 can be sandwiched between the one side portion in the axial direction of the longitudinal end portion 5 of the tube 2 and the outer tube portion when the press-fitting portion 31 is inserted toward the outer tube portion 22. Between 22.

The insertion portion 32 is disposed outside the tube 2 when the press-fitting portion 31 is pressed into the longitudinal end portion 5 side of the tube 2. The insertion portion 32 is cylindrical and is disposed on the other side in the axial direction of the inner ring 12. The insertion portion 32 has an inner diameter substantially the same as that of the press-fitting portion 31, and is provided so as to be included in an inner portion of one side of the fluid flow path 38 in the axial direction.

The insertion portion 32 is configured to have an outer diameter substantially larger than the outer diameter of the press-fitting portion 31. The press-fitting portion 31 is inserted into the outer tube portion 22 together with the one end portion 5 in the longitudinal direction of the tube 2. The mouthpiece 15 is inserted into the mouthpiece 15 of the outer tube 22 before the press-fitting portion 31 so as to cover the entire circumference from the inside in the radial direction and the entire length in the axial direction.

In the inserting portion 32, the fitting portion 35 is cylindrical, and is coaxially provided in succession to the other side end portion in the axial direction of the press-fitting portion 31. The fitting portion 35 is formed in a cylindrical shape having an inner diameter substantially the same as each of the inner diameter of the press-fitting portion 31 and the inner diameter of the tube 2 and has a shaft forming the fluid flow path 38. A part of the fluid flow path in the other side.

The fitting portion 35 has an outer diameter larger than that of the press-fitting portion 31 (except near the top of the bulging portion 39). When the inserting portion 32 is inserted into the mouth portion of the outer tube portion 22 At 15:00, the outer cylindrical portion 22 is approached from the inner side in the radial direction and abuts or is crimped. Here, the fitting portion 35 covers, contacts, or is crimped to the outer tube portion 22 over the entire circumference and the entire length in the axial direction.

The socket portion 36 has a cylindrical shape that can be press-fitted into the groove portion 29 of the joint body 11, and is coaxially protruded from the fitting portion 35 toward the other side in the axial direction. The socket portion 36 is formed in a cylindrical shape having an inner diameter slightly smaller than an outer diameter of the inner cylindrical portion 23 of the joint body 11 and having an outer diameter substantially the same as or larger than the outer diameter of the fitting portion 35. .

The socket portion 36 is press-fitted into the groove portion 29 when the insertion portion 32 is inserted into the receiving portion 15 of the outer cylindrical portion 22 to form a first sealing area 41 between the socket portion 36 and the inner cylindrical portion 23. And is crimped to the inner tube portion 23 from the outside in the radial direction. Here, the socket portion 36 is in contact with the inner cylinder portion 23 over the entire circumference and the entire length in the axial direction.

At this time, the socket portion 36 abuts or is crimped to the outer cylinder portion 22 from the inside in the radial direction. Here, the socket portion 36 is in contact with the outer cylinder portion 22 over the entire circumference and the entire length in the axial direction.

The contact portion 37 is cylindrical, and is disposed inward in the radial direction of the socket portion 36. The contact portion 37 is fitted from the fitting portion 35 in the axial direction of the inner ring 12 such that the protruding end portion 43 of the contact portion 37 is located on the fitting portion 35 side than the protruding end portion 44 of the socket portion 36. The portion 35 projects coaxially in the same direction as the socket portion 36 (the other in the axial direction of the fitting portion 35).

The contact portion 37 is formed in a cylindrical shape having an inner diameter substantially the same as the inner diameter of each of the fitting portion 35 and the inner diameter of the inner cylindrical portion 23 of the joint body 11. The contact portion 37 has a smaller inner diameter than the socket portion 36 so as to sandwich the protruding end portion 26 side of the inner tube portion 23 with one side portion of the socket portion 36 in the axial direction. Outer diameter.

In addition, when the contact portion 37 is pressed into the groove portion 29 when the socket portion 36 is pressed, the contact portion 37 is restricted from deforming and moving in the radial direction of the inner tube portion 23 caused by the press-fitting. A second seal region 42 is formed between 23 and is crimped to the inner tube portion 23 from one side in the axial direction. Here, the contact portion 37 contacts the inner tube portion 23 over the entire circumference.

The joint nut 13 includes a connecting portion 46. The connecting portion 46 is configured to be able to be inserted into the joint body 11 together with the one end portion 5 of the pipe 2 in the longitudinal direction so as to be connected to the joint body 11. In the state of the receiving portion 15, the one end portion 5 of the pipe 2 in the longitudinal direction is sandwiched between the radial direction and the press-fitting portion 31 and screwed to the outer peripheral portion of the joint body 11.

In this embodiment, the engaging nut 13 includes a pressing portion 47 in addition to the connecting portion 46. The joint nut 13 is further configured to further include a through hole in the shaft portion through which the tube 2 can pass, and to relatively move the tube 2 in the longitudinal direction in a state where the tube 2 passes through the through hole. Way, fit loosely to the aforementioned tube 2.

The connecting portion 46 is provided with a part of the through hole and a screwing portion capable of screwing with a screwing portion (the male screw portion 25) of the outer cylindrical portion 22 of the joint body 11. The connection portion 46 is cylindrical, and is disposed on the other side in the axial direction of the joint nut 13. The screwing portion of the connecting portion 46 is a female screw portion 49 and is provided along the axial direction on the inner peripheral portion of the connecting portion 46 so as to correspond to the screwing portion of the outer cylindrical portion 22 of the joint body 11.

The connection portion 46 is formed when the female threaded portion 49 is screwed into the male threaded portion 25 of the outer cylindrical portion 22 of the joint body 11 and screwed into the other axial direction, and surrounds the outer cylindrical portion 22 from the outside in the radial direction. And sandwiching the outer tube portion 22 and the one end portion 5 of the pipe 2 in the length direction with the press-fitting portion 31 of the inner ring 12 inserted between the outer tube portion 22 and the press-fitting portion 31.

At this time, the connecting portion 46 is in contact with the outer cylinder portion 22 over the entire circumference of the screwing region of the male screw portion 25 that is screwed to the outer cylinder portion 22 from the outside in the radial direction. And the one end portion 5 in the longitudinal direction of the tube 2 inserted into the receiving portion 15 of the outer tube portion 22 is indirectly connected through the outer tube portion 22 over the entire circumference covering the screwing region.

The pressing portion 47 is configured in a state where the pressing portion 31 is inserted into the receiving portion 15 together with the longitudinal end portion 5 of the tube 2, and the connecting portion 46 is pressed against the outer tube portion 22 along with the connecting portion 46. The male screw portion 25 is screwed in, and can press the longitudinal end portion 5 side of the tube 2 from one side in the axial direction toward the joint body 11 and press from the outside in the radial direction toward the pressing portion 31.

The pressing portion 47 is cylindrical and is disposed on one side in the axial direction of the joint nut 13. The pressing portion 47 is provided coaxially one after the other on the connecting portion 46 so that the inner peripheral portion is located inward in the radial direction than the inner peripheral portion of the connecting portion 46.

The pressing portion 47 has an inner diameter which is smaller than the inner diameter of the connecting portion 46 and is slightly larger than the outer diameter of the tube 2, and includes a remaining portion of the through hole.

The pressing portion 47 is sandwiched between the outer tube portion 22 and the longitudinal end portion 5 of the tube 2 inserted into the connecting portion 46 together with the pressing portion 31 of the inner ring 12 between the connecting portion 46 and the pressing portion 31. It is possible to arrange outside the outer cylinder portion 22 on one side in the axial direction, and sandwich the longitudinal end portion 5 side of the tube 2 with the press-fitting portion 31.

Specifically, the pressing portion 47 has a corner portion 48 provided on the other side in the axial direction of the inner peripheral portion thereof. When the connecting portion 46 is screwed into the male screw portion 25 of the outer tube portion 22, It is possible to press the longitudinal end portion 5 side of the tube 2 from the one side in the axial direction toward the joint body 11 through the corner portion 48 and press the corner portion 48 toward the press-fitting portion 31 from the outside in the radial direction. In other words, it can be clamped and held (clamped) with the press-fitting portion 31.

Here, the corner portion 48 is screwed into the male screw portion 25 of the outer cylinder portion 22 by the connecting portion 46, that is, by locking the engagement nut 13 of the joint body 11. Move toward the axial direction and press the expanded portion of the tube 2 so that the enlarged portion of the tube 2 (the portion along the first outer peripheral surface) is driven into the wedge by the bulging portion 39 so as to cover the entire circumference. Diameter section.

When joining the resin pipe joint 1 configured as described above to the pipe 2, for example, the joint nut 13 is first loosely fitted to the pipe 2. Next, in order to connect the inner ring 12 to the tube 2, one end portion 5 is attached to the press-in portion 31 from the opening portion 8 in the longitudinal direction, and coaxially while expanding the diameter of the tube 2 by the bulging portion 39. push into.

Then, the insertion portion 32 of the inner ring 12 located outside the tube 2 is inserted into the receiving portion 15 (inside the resin pipe joint 1) of the outer tube portion 22, and then the press-in portion 31 and the press-in portion are inserted. One end portion 5 in the longitudinal direction of the tube is inserted. Finally, the connecting portion 46 of the engaging nut 13 is screwed to the male screw portion 25 of the outer cylinder portion 22 and screwed to a predetermined position toward the joint body 11.

At the time of this screw-in, in this embodiment, the socket portion 36 can be pressed into the groove portion 29 so that a sealing force acts on the first sealing area 41 in the radial direction, and a seal can be formed. In a manner in which a force acts on the second seal region 42 in the axial direction, the contact portion 37 is crimped to the inner cylindrical portion 23 to lock the engagement nut 13.

In the resin pipe joint 1, the inner ring 12 and the joint nut 13 are made of the same resin material, and each has a property of shrinking in accordance with a change in ambient temperature. The shrinkage rate in the radial direction of the connection portion 46 of the joint nut 13 is set to be 0.05% or more larger than the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 12.

The inner ring 12 and the joint nut 13 are each made of a predetermined resin material. Preferably, the inner ring 12 and the joint nut 13 are each made of a fluororesin material as in this embodiment. Specific examples of the fluororesin material include PFA and PTFE.

The inner ring 12 is heated by the ambient temperature (including the temperature of the fluid flowing inside the resin pipe joint 1) rising from a normal temperature (approximately 25 ° C) to a predetermined value, and is heated by the ambient temperature from this state. It is cooled down to the vicinity of the normal temperature, and therefore, when the temperature change occurs first, the press-fitting portion 31 can be contracted in the radial direction from the original.

The joint nut 13 is heated by a predetermined temperature rising from the vicinity of the ambient temperature (including the temperature of the fluid flowing inside the resin-made pipe joint 1), and the ambient temperature is lowered from the state to the aforementioned normal temperature. It is cooled in the vicinity, so that when this temperature change first occurs, the connection portion 46 can be contracted in the radial direction from the original.

In addition, the connection portion 46 of the engaging nut 13 is set to shrink in the radial direction larger than the press-fitting portion 31 of the inner ring 12 when it is contracted. As described later, when the pressing portion 47 undergoes a temperature change, the pressing portion 47 also shrinks in the radial direction as compared with the original state.

For the inner ring 12 and the joint nut 13, for example, the diameter of the press-fitting portion 31 of the inner ring 12 can be adjusted by the presence or absence of heat treatment during the production of each of the joint nut 13 and the inner ring 12. There is a difference in a predetermined range between the shrinkage rate in the direction and the shrinkage rate in the radial direction of the connection portion 46 of the joint nut 13.

Here, the heat treatment is performed, for example, for the purpose of removing the internal distortion from the formed article when the inner ring 12 or the joint nut 13 is produced, and the formed article is subjected to a predetermined temperature for a predetermined time (for example, When the material is PFA or PTFE, it is about 180 minutes in the range of about 200 ° C to about 250 ° C, and when the material is ETFE, it is about 180 minutes in the range of about 120 ° C to 140 ° C) (annealing) .

Therefore, in the present embodiment, heat treatment is applied to the press-fit portion 31 of the inner ring 12 in order to make the shrinkage rate after the temperature change approximately zero (nearly shrink). On the other hand, the connection portion 46 (and the pressing portion 47) of the joint nut 13 is not subjected to heat treatment in order to make the shrinkage rate of the temperature variation larger than that of the pressing portion 31 of the inner ring 12.

The means for reducing the shrinkage rate in the radial direction of the press-fit portion 31 of the inner ring 12 and the shrinkage rate in the radial direction of the connection portion 46 of the joint nut 13 is not limited to the heat treatment. Whether or not, for example, means for appropriately adjusting the molding conditions of each of the inner ring 12 and the joint nut 13 may be used. Specifically, in the case of injection molding, if the molding conditions such as injection pressure, holding pressure, injection speed, and mold temperature during molding are different, the characteristics (residual stress, density) of the molded product will be different, making the molded product different. There is also a difference in shrinkage. Therefore, by changing the forming conditions between the inner ring 12 and the joint nut 13, it is also possible to cause a significant difference (a difference of 0.05% or more) in the shrinkage ratio between the two. The same applies to a method for making a difference in a predetermined range between the shrinkage rate in the radial direction of the press-fit portion 31 of the inner ring 12 and the shrinkage rate in the radial direction of the pressing portion 47 of the joint nut 13 described later.

In this embodiment, the difference between the shrinkage rate in the radial direction of the connection portion 46 of the joint nut 13 and the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 12 is set to about 0.05% to 10%. Value in the range. It is preferable that the difference between the shrinkage ratios of these two is set to a value in the range of about 0.05% to 5%. The difference between the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 12 and the shrinkage rate in the radial direction of the pressing portion 47 of the joint nut 13 is also described later.

With this structure, when the pipe 2 is joined to the resin pipe joint 1, the inner ring 12 and the joint nut 13 are heated after being heated by heat transfer from a fluid, etc., and then cooled (the load is present) At the time of thermal cycling), the connecting portion 46 of the joint nut 13 can be shrunk in the radial direction more than the press-fitting portion 31 of the inner ring 12.

Therefore, when the resin pipe joint 1 and the pipe 2 are joined, the shrinkage of the inner diameter of the connection portion 46 of the joint nut 13 is larger than the shrinkage of the outer diameter of the press-fitting portion 31 of the inner ring 12. The longitudinal end portion 5 of the tube 2 supported by the press-fitting portion 31 from the inside in the radial direction can be strengthened from the outside in the radial direction by the connection portion 46 overlapping in the radial direction through the outer tube portion 22 ( Clamping).

With this, when a pulling force is applied to the tube 2 so as to pull out the tube 2 from the resin pipe joint 1, the connection portion 46 of the joint nut 13 can be pressed toward the inside in the radial direction. The frictional force generated between the outer tube portion 22 and the tube 2 increases. Therefore, the pull-out resistance of the pipe 2 of the resin pipe joint 1 can be improved.

In this embodiment, the engagement nut 13 has the pressing portion 47, and the diameter of the pressing portion 47 of the engagement nut 13 is set to be smaller than the diameter of the press-fitting portion 31 of the inner ring 12 due to the shrinkage rate in the radial direction of the engagement nut 13. The shrinkage rate in the direction is larger. Therefore, similar to the connection portion 46, the reduction in the inner diameter of the pressing portion 47 of the joint nut 13 is larger than the reduction in the outer diameter of the press-fitting portion 31 of the inner ring 12. Since it is large, it is possible to increase the force for holding (holding) the radial end portion 5 side of the tube 2 from the outside in the radial direction by the pressing portion 47 (more specifically, the corner portion 48).

With this, when a pulling force is applied to the pipe in order to pull out the pipe 2 from the resin pipe joint 1, the pressing portion 47 of the joint nut 13 outside the joint body 11 and the pipe 2 can be made. The friction between them rises. Therefore, the pull-out resistance of the pipe 2 of the resin pipe joint 1 can be further improved.

The above-mentioned effect can be confirmed by performing a comparative experiment on the pull-out resistance of the tube. In this comparative experiment, Example 1 and Example 2 of the first embodiment of the present invention were prepared, and the same structure as the aforementioned resin pipe joint 1 was prepared, and the inner ring and the joint nut had the same structure as the present invention. Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are the differences in the shrinkage rates according to the first embodiment.

Next, the ambient temperature of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 was raised from normal temperature to about 200 ° C, and each was heated at 200 ° C for 1 hour. After that, by reducing the ambient temperature from about 200 ° C. to normal temperature, Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 were allowed to naturally cool.

In addition, the heating and natural cooling are performed in the state before each of Example 1, Example 2, Comparative Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 before joining to the tube (respective inner ring and joint nut). A state in which they are separated from each other and also from the joint body) are implemented for each of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

As shown in FIG. 2 and FIG. 3, for Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, the temperature of the inner ring was measured before and after the temperature fluctuation (heating). The outer diameter dimension of the press-fit part, the inner diameter dimension of the connection part that engages the nut, and the inner diameter dimension of the pressing part, and calculate the radial shrinkage of the press-fit part, the radial shrinkage of the connection part, and the radial direction of the press part Shrinkage.

Further, as shown in FIG. 4, the difference in shrinkage rate of the shrinkage rate in the radial direction of the connection portion of the joint nut with respect to the shrinkage rate in the radial direction of the press-fit portion of the inner ring is calculated. In addition, the difference between the shrinkage rate in the radial direction of the pressing portion of the engagement nut and the shrinkage rate in the radial direction of the press-fitting portion of the inner ring was calculated.

Here, Example 1 includes an inner ring made of PFA and a joint nut made of PFA. In Example 1, the inner ring system was produced so that the press-fit portion before and after heating did not shrink. The joint nut is manufactured in such a manner that the radial direction of the connection portion contracts and the pressing portion contracts before and after heating.

In this way, the shrinkage rate in the radial direction of the connection portion that engages the nut has a difference of 0.50% with respect to the shrinkage rate in the radial direction of the press-fit portion of the inner ring. In addition, the shrinkage rate in the radial direction of the pressing portion of the joint nut is set to be 0.11% higher than the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Example 2 is provided with an inner ring made of PTFE and a joint nut made of PTFE. In Example 2, the inner ring system was produced so that the press-fit portion before and after heating did not shrink. The joint nut is manufactured so that the connection portion shrinks and the pressing portion shrinks before and after the heating.

In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is set to be 0.07% higher than the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the joint nut is set to be 0.05% higher than the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 1 includes an inner ring made of PFA and a joint nut made of PFA. In Comparative Example 1, the inner ring system was produced so that the press-fit portion before and after heating did not shrink. The joint nut is manufactured so that the connection portion does not shrink and the pressing portion does not shrink before and after the heating.

In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is the same as the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the engagement nut is the same as the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 2 includes an inner ring made of PFA and a joint nut made of PFA. In Comparative Example 2, the inner ring system was produced so that the press-fit portion before and after heating would shrink. The joint nut is manufactured so that the connection portion shrinks and the pressing portion shrinks before and after heating.

In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is reduced by a difference of 0.04% with respect to the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the joint nut is reduced by 0.43% with respect to the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 3 includes an inner ring made of PTFE and a joint nut made of PTFE. In Comparative Example 3, the inner ring system was produced so that the press-fit portion before and after heating did not shrink. The joint nut is manufactured so that the connection portion does not shrink and the pressing portion does not shrink before and after heating.

In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is the same as the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the engagement nut is the same as the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 4 includes an inner ring made of PTFE and a joint nut made of PTFE. In Comparative Example 4, the inner ring system was produced so that the press-fit portion before and after heating would shrink. The joint nut is manufactured in the same manner as the inner ring, before and after heating, the connection portion shrinks and the pressing portion shrinks.

In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is made to be 0.02% higher than the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the engaging nut is the same as the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

In addition, for each of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, a PFA-made joint was attached to assemble the joint body corresponding to the inner ring and the joint nut. Tube, reload thermal cycle (normal temperature → high temperature (about 200 ° C) → normal temperature). The pull-out resistance ratio of the tube was measured before and after the load thermal cycle.

The so-called pull-out resistance ratio of the tube is determined by measuring the pull-out resistance value of the tube after the 0th to 5th thermal cycles, and comparing the values before the thermal cycle (that is, when the number of thermal cycles is 0). The pull resistance value is, specifically, the pull resistance of a tube after thermal cycling divided by the pull resistance before thermal cycling.

From the measurement results shown in FIG. 5, it can be seen that the pull-out resistance ratio of the tube in Examples 1 and 2 is larger than that in Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. That is, according to the first embodiment of the present invention, it can be seen that the pull-out performance of the pipe is improved even when the thermal cycle is repeatedly applied.

Next, a second embodiment of the present invention will be described with reference to the drawings.

The resin pipe joint 101 according to the second embodiment of the present invention is different from the resin pipe joint 1 of the first embodiment in that the inner ring 112 and the joint nut 113 are made of different resin materials. Except for this difference, the resin pipe joint 101 of this embodiment is substantially the same as the resin pipe joint 1 of the first embodiment. Therefore, the resin pipe joint 101 is as shown in FIG. 6. In general, the same reference numerals are given to the constituent elements that are substantially the same as the constituent elements of the resin pipe joint 1 of the first embodiment, and detailed descriptions thereof are omitted.

In the resin pipe joint 101, the inner ring 112 and the joint nut 113 are made of resin materials different from each other, and each has a property of shrinking in accordance with a change in ambient temperature. The shrinkage rate in the radial direction of the connection portion 46 of the joint nut 113 is set to be 0.05% or more larger than the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 112. That is, the joint nut 113 is made of a resin material having a larger shrinkage rate than that of the resin material used in the inner ring 112.

Here, the resin materials different from each other include not only those having different resin names, but also those having the same resin name but different resin classifications. That is, if the resin classification is different, it will be caused by the difference in molecular structure, molecular weight, crystallinity, etc., which will cause MFR (Melt Flow Rate) during molding and flex life (flex life) after molding. However, the shrinkage of the molded product is poor. Therefore, between the inner ring 112 and the joint nut 113, by using different resin graded resin materials, it is possible to cause a significant difference (a difference of 0.05% or more) in the shrinkage ratio of the two. .

The inner ring 112 and the joint nut 113 are each made of a predetermined resin material. Preferably, the inner ring 112 and the joint nut 113 are each made of a fluororesin material as in this embodiment. Specific examples of the fluororesin material include PFA, PTFE, and ETFE.

The inner ring 112 is heated by the ambient temperature (including the temperature of the fluid flowing inside the resin-made pipe joint 101) rising from a normal temperature (approximately 25 ° C) by a predetermined value, and is heated by the ambient temperature from this state. It is cooled down to the vicinity of the normal temperature, and therefore, when the temperature change occurs first, the press-fitting portion 31 can be contracted in the radial direction from the original.

The joint nut 113 is heated by a predetermined temperature rising from the vicinity of the ambient temperature (including the temperature of the fluid flowing inside the resin-made pipe joint 101) to a predetermined value, and the ambient temperature is lowered to the normal temperature from the state. It is cooled in the vicinity, so that when this temperature change first occurs, the connection portion 46 can be contracted in the radial direction from the original.

Preferably, the inner ring 112 and the engagement nut 113 include the press-fitting portion 31 and the connection portion 46, respectively, and are provided in a ratio when heating (when a predetermined amount of heat is given by a change in ambient temperature). It expands more before the heat, and then shrinks more when it cools down (when the heat is captured by changes in ambient temperature) than when it was the first time (before the initial heat application).

In addition, the connection portion 46 of the engagement nut 113 is set to shrink more in the radial direction than the press-fitting portion 31 of the inner ring 112 when it is contracted.

The inner ring 112 and the joint nut 113 are as described above. Although the material of the resin material used is different, the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 112 and the joint can be made. There is a difference in a predetermined range between the shrinkage rates in the radial direction of the connection portion 46 of the nut 113, but the difference in shrinkage rates between the two may be further increased by the presence or absence of heat treatment or adjustment of the molding conditions. Specifically, the heat treatment may be applied only to the inner ring 112 to reduce the shrinkage after temperature fluctuation to almost zero (there is almost no shrinkage), and the difference in shrinkage between the two may be further increased. The same applies to a method of making a difference in a predetermined range between the shrinkage rate in the radial direction of the press-fit portion 31 of the inner ring 112 and the shrinkage rate in the radial direction of the pressing portion 47 of the joint nut 113 described later.

Here, the heat treatment is, for example, for the purpose of removing internal distortions from the formed article during the production of the inner ring 112, and the formed article is subjected to a predetermined temperature for a predetermined time (for example, the material is PFA or PTFE). It is about 180 minutes in the range of about 200 ° C to about 250 ° C and about 180 minutes in the range of about 120 ° C to 140 ° C when the material is ETFE) (annealing).

In this embodiment, the difference between the shrinkage rate in the radial direction of the connection portion 46 of the joint nut 113 and the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 112 is set to about 0.05% to 10%. Value in the range. It is preferable that the difference between the shrinkage ratios of these two is set to a value in the range of about 0.05% to 5%. The difference between the shrinkage rate in the radial direction of the press-fitting portion 31 of the inner ring 112 and the shrinkage rate in the radial direction of the pressing portion 47 of the joint nut 113 described later is also the same.

With such a configuration, in a state where the pipe 2 is joined to the resin pipe joint 101, the inner ring 112 and the joint nut 113 are cooled after being heated by heat transfer from a fluid or the like (the load is present) At the time of thermal cycling), the connecting portion 46 of the engaging nut 113 can be shrunk in the radial direction more than the press-fitting portion 31 of the inner ring 112.

Therefore, when the resin pipe joint 101 and the pipe 2 are joined, the diameter reduction of the inner diameter of the connecting portion 46 of the joint nut 113 is larger than the diameter reduction of the outer diameter of the press-fitting portion 31 of the inner ring 112. Therefore, the longitudinal end portion 5 of the tube 2 supported by the press-fitting portion 31 from the inside in the radial direction can be strengthened from the outside in the radial direction by the connecting portion 46 overlapping with the outer cylinder portion 22 in the radial direction. Holding (holding) force.

With this, when a pulling force is applied to the tube 2 so that the tube 2 is pulled out from the resin pipe joint 101, the connection portion 46 of the joint nut 113 can be pressed toward the inside in the radial direction. The frictional force generated between the outer tube portion 22 and the tube 2 increases. Therefore, the pull-out resistance of the pipe 2 of the resin pipe joint 101 can be improved.

In this embodiment, the engagement nut 113 has the pressing portion 47, and the diameter of the pressing portion 47 of the engagement nut 113 is set to be smaller than the diameter of the pressing portion 31 of the inner ring 112 because of the shrinkage rate in the radial direction. The shrinkage rate in the direction is larger. Therefore, similar to the connection portion 46, the diameter reduction of the inner diameter of the pressing portion 47 of the engagement nut 113 is greater than the diameter reduction of the outer diameter of the pressing portion 31 of the inner ring 112. Since it is large, it is possible to increase the force for holding (holding) the radial end portion 5 side of the tube 2 from the outside in the radial direction by the pressing portion 47 (more specifically, the corner portion 48).

With this, when a pulling force is applied to the pipe in order to pull out the pipe 2 from the resin pipe joint 101, the pressing portion 47 of the joint nut 113 outside the joint body 11 and the pipe 2 can be made. The friction between them rises. Therefore, the pull-out resistance of the pipe 2 of the resin pipe joint 101 can be further improved.

The above-mentioned effect can be confirmed by performing a comparative experiment on the pull-out resistance of the tube. In this comparative experiment, Example 3 and Example 4 of the second embodiment of the present invention were first prepared, and the same structure as the aforementioned resin pipe joint 101 was prepared, and the inner ring and the joint nut had the same structure as the present invention. Comparative Example 5, Comparative Example 6, and Comparative Example 7 are differences in the shrinkage rates according to the second embodiment.

Next, the ambient temperature of Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 was raised from normal temperature to about 200 ° C, and each was heated at 200 ° C for 1 hour. Then, Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 were naturally cooled by reducing the ambient temperature from about 200 ° C to normal temperature.

In addition, the heating and natural cooling are performed in the states before Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 before being joined to the tube (the respective inner rings and joint nuts are separated from each other and separated from A state where the joint body is also separated) was implemented for each of Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7.

As shown in Fig. 7 and Fig. 8, for Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7, the outside of the press-fit portion of the inner ring was measured before and after the temperature fluctuation (heating), respectively. The diameter dimension and the inner diameter dimension of the connecting portion of the joint nut and the inner diameter dimension of the pressing portion are used to calculate the shrinkage ratio in the radial direction of the press-fit portion, the shrinkage ratio in the radial direction of the connection portion, and the shrinkage ratio in the radial direction of the pressing portion.

Further, as shown in FIG. 9, the difference in shrinkage rate between the shrinkage rate in the radial direction of the connection portion of the joint nut and the shrinkage rate in the radial direction of the press-fit portion of the inner ring is calculated. In addition, the difference between the shrinkage rate in the radial direction of the pressing portion of the engagement nut and the shrinkage rate in the radial direction of the press-fitting portion of the inner ring was calculated.

Here, Example 3 includes an inner ring made of PTFE and a joint nut made of PFA. In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is set to be 0.45% higher than the shrinkage rate in the radial direction of the press-fit portion of the inner ring. In addition, the shrinkage rate in the radial direction of the pressing portion of the engagement nut is set to be 0.06% higher than the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Example 4 includes an inner ring made of PTFE and a joint nut made of ETFE. In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is set to be 0.34% higher than the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the joint nut is set to be 0.06% higher than the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 5 includes an inner ring made of PFA and a joint nut made of PFA. In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is reduced by a difference of 0.04% with respect to the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the joint nut is reduced by a difference of 0.44% with respect to the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 6 includes an inner ring made of ETFE and a joint nut made of ETFE. In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is reduced by a difference of 0.02% with respect to the shrinkage rate in the radial direction of the press-fitting portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the joint nut is set to be 0.30% lower than the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

Comparative Example 7 includes an inner ring made of PTFE and a joint nut made of PTFE. In this way, the shrinkage rate in the radial direction of the connection portion of the joint nut is made to be 0.02% higher than the shrinkage rate in the radial direction of the press-fit portion of the inner ring. The shrinkage rate in the radial direction of the pressing portion of the engagement nut is the same as the shrinkage rate in the radial direction of the press-fitting portion of the inner ring.

In addition, for each of Example 3, Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7, a pipe made of PFA was joined by assembling a joint body corresponding to the inner ring and the joint nut, and reloaded Thermal cycling (normal temperature → high temperature (about 200 ° C) → normal temperature). The pull-out resistance ratio of the tube was measured before and after the load thermal cycle.

The so-called pull-out resistance ratio of the tube is determined by measuring the pull-out resistance value of the tube after the 0th to 5th thermal cycles, and comparing the values before the thermal cycle (that is, when the number of thermal cycles is 0). The pull-out resistance value is, specifically, the pull-out resistance of the tube after thermal cycling divided by the pull-out resistance of the tube before thermal cycling.

From the measurement results shown in FIG. 10, it can be seen that the pull-out resistance ratios of the pipes in Examples 3 and 4 are larger than those in Comparative Examples 5, 6 and 7. That is, according to the second embodiment of the present invention, it can be seen that the pull-out performance of the riser pipe can be improved even when the thermal cycle is repeated.

In addition, considering the foregoing teachings, it can be seen that the present invention can take various modified forms and modified forms. Therefore, it is understood that the present invention can be implemented by methods other than those described in the present specification within the scope of the attached patent application.

Claims (4)

    A resin pipe joint that can be joined to the pipe in a state where one end portion of the pipe in the longitudinal direction is inserted into the pipe body includes a joint body having a cylindrical portion capable of inserting one end portion in the longitudinal direction of the pipe; an inner ring, The press-fitting portion has a press-fitting portion that can be press-fitted to the lengthwise one-end portion side of the tube, and can be pressed to the length-wise end of the tube in a state of being press-fitted to the lengthwise one-end portion side of the tube. And the joint nut is provided with a connecting portion for connecting the press-fitting portion and the longitudinal end of the pipe to the joint body in order to connect the longitudinal end portion side of the pipe to the joint body. In a state in which the tube portion is inserted into the cylindrical portion together, the tube is screwed to the outer peripheral portion of the joint body so as to sandwich one end portion of the tube in the longitudinal direction between the radial direction and the press-fitting portion; the inner ring and the joint nut. Is made of a resin material and each has a property of shrinking in accordance with a change in ambient temperature, and the shrinkage rate in the radial direction of the joint portion of the joint nut, It is set to be larger than the shrinkage in the radial direction of the inner ring press-fitted portion of 0.05% or more.         The resin pipe joint according to claim 1, wherein the inner ring and the joint nut are made of the same resin material.         The resin pipe joint according to claim 1, wherein the inner ring and the joint nut are made of different resin materials.         The resin pipe joint according to any one of claim 1 to claim 3, wherein the joint nut includes a pressing portion that is inserted into the pressing portion together with the one end portion in the longitudinal direction of the pipe. In the state of the tube portion, as the connecting portion is screwed into the outer peripheral portion of the tube portion, one end portion side of the longitudinal direction of the tube can be pressed from the outside in the radial direction toward the pressing portion; the pressing portion of the joint nut The shrinkage rate in the radial direction is set to be larger than the shrinkage rate in the radial direction of the press-fit portion of the inner ring.